linux-kernel - Re: [PATCH 1/3] retpolines: Only enable retpoline when compiler support it

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 30 Oct 2018 09:32:10 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Zhenzhong Duan <zhenzhong.duan@...cle.com>
Cc:     Linux-Kernel <linux-kernel@...r.kernel.org>, mingo@...hat.com,
        luto@...nel.org, konrad.wilk@...cle.com, dwmw@...zon.co.uk,
        tglx@...utronix.de, Srinivas REDDY Eeda <srinivas.eeda@...cle.com>,
        bp@...e.de, daniel@...earbox.net, yamada.masahiro@...ionext.com,
        michal.lkml@...kovi.net, hpa@...or.com
Subject: Re: [PATCH 1/3] retpolines: Only enable retpoline when compiler
 support it

On Mon, Oct 29, 2018 at 11:55:04PM -0700, Zhenzhong Duan wrote:
> Since retpoline capable compilers are widely available, make
> CONFIG_RETPOLINE hard depend on it.
> 
> Change KBUILD to use CONFIG_RETPOLINE_SUPPORT to avoid conflict with
> CONFIG_RETPOLINE which is used by kernel.
> 
> With all that stuff, the check of RETPOLINE is changed to
> CONFIG_RETPOLINE.

So what happens when we select CONFIG_RETPOLINE but do not have
RETPOLINE_SUPPORT ? From a quick reading we'll silently build a
!retpoline kernel. I would expect a build failure.